The present invention relates to integrated circuit packages, in particular, those containing die that generate substantial levels of electromagnetic emissions.
Computer systems can emit electromagnetic radiation at various frequencies. Those emissions may cause undesirable electromagnetic interference (xe2x80x9cEMIxe2x80x9d) with the circuitry of the computer system and other electronic equipment near the computer system. For that reason, the FCC has enacted certain Open Chassis EMI regulations that impose limits on the electromagnetic emissions that such systems generate. 47 CFR xc2xa715.109. These limits are specified in Table 1 below.
Currently, most of the EMI that computer motherboards cause results from emissions produced by the packaged integrated circuits (xe2x80x9cICsxe2x80x9d) that are mounted, or coupled, to the motherboard. To block (or reduce) the emissions that those parts release, various types of Faraday cages (or other sealing/covering apparatus) may be placed over them. Such devices, however, add cost to the system, may occupy scarce motherboard space, and may impose challenging signal routing requirements. As a consequence, using such devices to reduce the EMI that these packaged ICs cause is not a particularly attractive solution.
Accordingly, there is a need for an improved mechanism for reducing IC generated EMI. There is a need for such a mechanism that can be integrated into standard component designs without requiring significant modification. The packaged IC of the present invention includes such a mechanism.